共沉淀法制备CoAl2 O4陶瓷颜料及其呈色机理研究

采用共沉淀法制备CoAl2 O4陶瓷颜料，并通过XRD、SEM和XPS表征陶瓷颜料的组成、形貌和元素价态，研究Co/Al比、溶液pH值和煅烧温度对CoAl2 O4陶瓷颜料呈色的影响，并探讨其呈色机理。结果表明：所得CoAl2 O4陶瓷颜料均具有典型的尖晶石结构，当Co/Al比为0.7∶2、溶液pH值为11、煅烧温度为1200℃时可以获得彩度较高的蓝色CoAl2 O4陶瓷颜料。 CoAl2 O4陶瓷颜料的呈色变化主要与所得产物中Co元素的价态有关，当Co含量过高或者前驱体溶液的pH值较大时，产物中含有Co3 O4( Co4+)，进入CoAl2 O4后形成固溶体导致其晶格发生畸变，从而使得陶瓷颜料呈现绿色。

Fabrication and Coloration Mechanism of CoAl2 O4 Ceramic Pigment by Co-precipitation Method

Cobalt aluminate ( CoAl2 O4 ) ceramic pigment powders were fabricated by co-precipitation method. Compositions, morphologies and valence state of CoAl2 O4 ceramic pigment powders were characterized by XRD, SEM and XPS. Effects of Co/Al ratio, pH value and calcination temperature on color properties of the samples were also investigated. Finally, coloration mechanism of the pigment was discussed. The results show that the resulting samples are of the typical spinel structure. The blue CoAl2 O4 ceramic pigment with high chroma was obtained when the Co/Al ratio is 0. 7∶2, pH value is 11 and calcination temperature is 1200 ℃. And, the color change of CoAl2 O4 ceramic pigments is mainly related with the valence of Co elements in the products. CoAl2 O4 ceramic pigments contain Co3 O4 ( Co4+) when the Co content or pH of the precursor solution is high, then crystal lattice distortion could be occured when Co3 O4 entered into the CoAl2 O4 to form a solid solution, resulting in a green ceramic pigment.